The iPhone matters now more than ever to Apple

The iPhone has been the single-most important product driving Apple's business in recent years. In particular, following the release of the iPhone 6 and the iPhone 6 Plus last year, Apple has been delivering record-breaking sales and profits, resulting in all-time high share prices as well.

This chart, put together for us by Statista, further illustrates this point. The iPhone's revenue as a percentage of Apple's total sales has grown exponentially since 2007, showing the company's ever-growing dependence on its smartphone. In the March quarter of this year, the iPhone accounted for 69% of Apple's revenue, up from just 53% in the second quarter of 2013, and 40% in the second quarter of 2010.

Apple is expected to sell 49.4 million iPhones, according to Fortune's roundup of analyst estimates, while Bloomberg expects it to be around 48.8 million this quarter.

"Apple will be the iPhone company for the foreseeable future. The iPhone's gravitational pull is simply too strong for any new product or service to reach escape velocity and become the next big thing for Apple in the near-term," wrote Neil Cybart, an independent Apple analyst, in his earnings preview.